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Wildfire Smoke Update
for
Wednesday, September 26, 2012 3:30 PM

Satellite Photos | Locations and Smoke Conditions


Today's Report and Forecast Today's Summary
Particulate concentrations have held fairly steady throughout the day today at monitoring locations, and hourly concentrations are lower than we have seen for the last few days. This, in turn, has brought the cumulative particulate averages down as well, which is welcomed news to many folks across western Montana. Cumulative smoke exposures have dropped to UNHEALTHY in Hamilton. Although the wildfire smoke is still unhealthy for the general population at these levels, it has been over a week since the Bitterroot Valley has seen air quality below HAZARDOUS and VERY UNHEALTHY levels. Cumulative concentrations have dropped to levels that are UNHEALTHY FOR SENSITIVE GROUPS in Missoula, Frenchtown, Butte, Helena, Libby, the Flathead Valley, and Seeley Lake, though hourly concentrations are also GOOD to MODERATE in all these locations. Air quality conditions are very similar to this across most western valleys that are not mentioned. However, cumulative concentrations have become MODERATE in Bozeman, with GOOD hourly observations. Some southwest and southern regions are all GOOD today, like Dillon and West Yellowstone. The central plains are GOOD this afternoon, but the cold front still has yet to pass far eastern Montana, where air quality is generally MODERATE.

A ridge of high pressure will build back into the Northern Rockies by Thursday and will last through early next week. This will bring more stable air to our region, which should result in an increase of wildfire smoke and poor air quality across western Montana. Another weak and dry cold front will pass across Montana late Saturday through Sunday, which should temporarily help to improve the air quality—much like we saw today. However, another ridge of high pressure builds in behind that cold front and air quality will decrease again. This will last for the beginning of next week. The weather system that I have mentioned for the last two days is still showing up in the long-term forecast models. There are still many uncertainties in the exact timing and in how much precipitation there may be. Despite uncertainties in the details, the fact remains that we are still expecting a fall-like weather system by the middle or end of next week which would bring cool temperatures, clear the smoke, and may even provide some much-needed precipitation over the region.
Cumulative smoke exposures have dropped to UNHEALTHY in Hamilton. Although the wildfire smoke is still unhealthy for the general population at these levels, it has been over a week since the Bitterroot Valley has seen air quality below HAZARDOUS and VERY UNHEALTHY levels. Cumulative concentrations have dropped to levels that are UNHEALTHY FOR SENSITIVE GROUPS in Missoula, Frenchtown, Butte, Helena, Libby, the Flathead Valley, and Seeley Lake, though hourly concentrations are also GOOD to MODERATE in all these locations. Air quality conditions are very similar to this across most western valleys that are not mentioned. However, cumulative concentrations have become MODERATE in Bozeman, with GOOD hourly observations. Some southwest and southern regions are all GOOD today, like Dillon and West Yellowstone. The central plains are GOOD this afternoon, but the cold front still has yet to pass far eastern Montana, where air quality is generally MODERATE.
Residents near active fires and under plumes aloft need to remain aware of current conditions and use the visibility guidelines to guide their activity decisions as the situation changes.

Air Quality Bureau
Montana Department of Environmental Quality
Phone: (406) 444-3490
Email: DEQMTSmoke@mt.gov




This is the visible satellite image from 2:30 this afternoon. Clouds are visible across the region, though skies have been clearing across the central plains. 

This is the visible satellite image from 2:30 this afternoon. Clouds are visible across the region, though skies have been clearing across the central plains.


 
This is a high-definition, colored satellite image from 1:00 this afternoon. It was not visible in the black-and-white satellite image above, but now we can see the smoke that is across parts of western Montana and eastern Idaho. That smoke will slowly travel over western Montana, and under the stable ridge of high pressure, we can expect air quality to decrease again in the coming days.

This is a high-definition, colored satellite image from 1:00 this afternoon. It was not visible in the black-and-white satellite image above, but now we can see the smoke that is across parts of western Montana and eastern Idaho. That smoke will slowly travel over western Montana, and under the stable ridge of high pressure, we can expect air quality to decrease again in the coming days.


This morning’s analysis from NOAA’s satellite services division shows the active fires in Montana and the smoke plumes combining and spreading downwind (the analyzed smoke is based on yesterday’s satellite coverage, the fire detects are based on last nights satellite coverage).

This morning’s analysis from NOAA’s satellite services division shows the active fires in Montana and the smoke plumes combining and spreading downwind (the analyzed smoke is based on yesterday’s satellite coverage, the fire detects are based on last nights satellite coverage).

Red indicates hot spot detected. Green represents thin smoke, yellow is moderate smoke, and purple is dense smoke. Fire size is exaggerated for visibility at this scale. To identify individual fires on graphic above go here: http://activefiremaps.fs.fed.us/lg_fire2.php 




Real time particulate information is currently available in most of the larger urban areas from MTDEQ's Today's Air website.

Today's particulate report below compares particulate levels received from DEQ's
reporting stations with MTDEQ’s Health Effect Categories.

Locations and severity of PM 2.5 particulate values over the past 24 hours from the time above.
Health Effects Categories City
  Hazardous  
  Very Unhealthy  
  Unhealthy  Hamilton B24, B8
  Unhealthy for Sensitive Groups  Seeley Lake B24, B8
Butte B24, B8
Helena B24
Missoula B24
Frenchtown B24
Flathead Valley B24
Libby B24
  Moderate

 Bozeman B24, B8
Billings B24
Sidney B24
Great Falls B24
 

  Good

 West Yellowstone
Dillon
 

B1(x) One-hour BAM value (number of values)
B8(x) Eight-hour average BAM
B24 24 hour  average BAM value
Local impacts in areas immediately adjacent to active fires are expected to exceed some or all of the advisory levels.  DEQ recommends the use of local visibility guidelines to evaluate possible health risks and make informed activity decisions.